mail/dovecot-*: bump after update mail/dovecot as described in Makefile

mail/dovecot updated in 72dd8d2ee676.

While here:

• remove GNU_CONFIGURE_MANPREFIX;
• replace PORTVERSION on DISTVERSION.

PR: 280866
Approved by: ler (maintainer)
MFH: 2024Q3

(cherry picked from commit 6dcc035f8311c4be6ecc61a1d139b78b603b3aab)